JPS5937699A - Device for firing discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device using an inverter, and provides a configuration that achieves reduction in power loss.

Figure 1 shows an example of a conventional discharge lamp lighting device, in which the AC side ends of a rectifier circuit 1b are connected to both ends of an AC power source 1a such as a quotient qJ m source to form a DC power source 1, and Connect inverter 2 and connect inverter 2
A fluorescent rung 4, which is a load discharge lamp, is connected to the output end of a double-shaped oscillation transformer 8. The inverter 2 is of the well-known two-stone bushgel type, and a resonance capacitor 5 is connected in parallel to the primary winding 8a of an oscillation transformer 3 to which a constant current inductor L is connected in series. Two oscillating transistors 6 and 7 are connected to both ends of the oscillating transistor 5, and both ends of the feedback winding 3b of the oscillating transformer 8 are connected to each base of the oscillating transistor 7. Then, the oscillation transformer 8 is provided with a drive winding 8 for base drive, the AC side ends of the rectifier circuit 9 are connected to both ends of the 1゛ fiber wire 8, and the smoothing capacitor io is connected to the DC side end of the rectifier circuit 9. The smoothing capacitor 1o is connected at both ends with a base resistor and an oscillation transistor 6 between the collector and emitter of the AC voltage source (NPN type synchronizing transistor 11, which turns on and off in synchronization with the source voltage). The series circuit between the base resistor 13 and the base-emitter series circuit of the other oscillation transistor 7 are connected in parallel. It is connected to the.

The operation of such a discharge lamp lighting device will be explained below.

When the AC power supply 1a is turned on, a constant current inductor is connected between the base, emitter, and lid of the starting resistor 14 and the synchronizing transistor 11, and the oscillation transistor 6.7 [τ base current source is supplied, and eventually One of the oscillation transistors turns on, and the inverter 2 starts oscillating. When the inverter 2 starts oscillating, an oscillation output is induced in the drive winding 8, and this output is smoothed into DC by the smoothing capacitor lO. From then on, this smoothed output becomes the collector current source of the synchronization transistor 11, that is, the oscillation transistor 6. The inverter 2 continues to oscillate as a base current source of .7.

In this way, the starting resistor 14 serves to supply the base current of the oscillation transistor 6.7 only when oscillation starts when the inverter 2 is powered on, and once oscillation has started, the smoothing capacitor 10 supplies the oscillation transistor 6. Since the starting resistor 14 serves as a base current source for the transistors y, taro, and 7, the resistance value of the starting resistor 14 may be large enough to drive the synchronizing transistor 11. However, when the load is heavy, for example when a fluorescent rung 4 with a preheating filament is used as the load as in the case shown in FIG. If the value is too large, no voltage has yet been generated in the smoothing capacitor 10, and the pace current of the oscillation transistor 6.7 will be supplied from the DC power supply l side through the entire starting resistor 14, so that the first oscillation transistor 6. .7 may not be able to obtain a sufficient pace current, and there may be a problem that the inverter 2 may not be able to start oscillation.

Therefore, the resistance value of the starting resistor 14 cannot be made very large, and there is a drawback that the power loss generated in the starting resistor 14 during the operation of the inverter 2 cannot be sufficiently reduced.

The synchronizing transistor 11 supplies a pace current to the oscillating transistor 6.7 in synchronization with the pulsating power of the AC power supply supplied to the inverter 2, thereby preventing abnormal oscillation of the inverter 2 and stabilizing the operation. This contributes to the

On the other hand, in the case of the one in Fig. 1, as shown in Fig. 2, the DC power supply l
Inverter 2#' over the entire range of pulsating output voltage V1 of
One oscillation output v2 is generated, but the oscillation output near the zero point of the pulsating voltage does not contribute to the lighting of the fluorescent rung 4, and the fluorescent rung 4 is re-ignited at the beginning of each half cycle of the pulsating flow. The interval Tl in the table is simply oscillation under no-load condition, and the oscillation in this interval TI is one of the causes of the power loss of the entire tabletop.

The present invention was made in view of the drawbacks of the conventional example, and
It is an object of the present invention to provide a discharge lamp lighting device that achieves low oil vR power by suppressing power loss in a starting resistor portion and power loss in a no-load oscillation section.

The present invention will be described below based on embodiments shown in the drawings.

FIG. 8 shows an embodiment of the present invention, in which the starting resistor 14 is made up of two resistors 14a and 14b connected in series, and in parallel with the resistor 14b, at least at a predetermined phase from the zero point during each cycle of the pulsating voltage v1. By connecting a switch S that opens only in a predetermined section including the section Tl up to
The structure differs from that shown in Fig. 1 in that it forms a . At this time, each resistance value is selected to be high so that the inverter 2 does not oscillate in the combined resistance value of the series circuit of the resistors 14a and 14b.

In this embodiment, as shown in FIG.
In the section T2 where is on, the resistor 14a, which is a low resistance part,
The smoothing capacitor 10 is connected to the DC power supply l between the base and collector of the switch S and the synchronizing transistor 11.
is initially charged, first a sufficient voltage is generated in the smoothing capacitor 1o as a power source for base drive, and also a sufficient base current is supplied to the synchronizing transistor 11 during the switch S closing period T2, and the synchronizing transistor 11 is turned on, and the inverter 2 starts oscillating using the smoothing power supply →lIO as the base power supply.

Note that the t:l inverter 2 is set not to oscillate due to the current flowing through the series circuit of the resistors 14a and 14b, which are high resistance parts, but the resistor 14@ and the
The base current of the synchronizing transistor 11 flowing through the synchronizing transistor 11 is set to be sufficiently large.

Even if the smoothing capacitor 10 is not sufficiently initially charged and sufficient voltage is not yet generated across it, the base current itself becomes a sufficient base current for the oscillation transistor 6.7, and the conventional The inverter 2 can start oscillating much more easily than the above.

After the inverter 2 starts oscillating, the oscillation output induced in the drive winding 8 causes the smoothing capacitor l to rise.

maintains a sufficient terminal voltage, and thereafter the inverter 2 does not generate an oscillation output during the ON period T2 of the switch S.
The output voltage v2 as shown in the figure is obtained, and the no-load oscillation state is almost eliminated, resulting in small power loss and extremely high efficiency.

Figure 5 shows a bypass capacitor used as switch S.
This shows a specific circuit example using the capacitor ■6, where the terminal voltage vCFi of the capacitor 6 is a value larger than the output voltage vl only in an interval T3 that includes an interval T from the zero point of the pulsating output voltage V of the DC power supply 1 to a predetermined phase. Therefore, during this interval T3, t
j capacitor 16 fulfills the switch-off function, and the collector-emitter voltage V (J
As shown in FIG. 6, the oscillation of the oscillation of the oscillation of the oscillation of the oscillation of the oscillations of the oscillations of the oscillations stopped during the interval 1's is stopped, and sufficient optical output can be obtained while suppressing power loss.

By using variable resistors for the resistors 14a and 14b or changing the value of the capacitor 16 with a switch, it is possible to stop the oscillation output only during an arbitrary period including the zero point of the pulsating output voltage vl. Outflow power! "Pressure V1
It is possible to perform rung dimming while eliminating the no-load oscillation portion during each cycle, and an efficient dimming device can be obtained.

Furthermore, in each of the above embodiments, the oscillation transformer 8 is provided with a drive winding that detects the output corresponding to the AC output of the oscillation transformer 8, but it may be provided in each collector circuit of the oscillation transistor 6.7. , 2 of constant current inductor L
Of course, it may be provided on the next side.

As described above, the present invention provides an oscillation capacitor that smooths the AC output corresponding to the AC oscillation output of the inverter and supplies the base current to the oscillation transistor between the base and emitter of the oscillation transistor. Insert a synchronization transistor that synchronizes the base current of the transistor with the pulsating output voltage of the DC power supply, connect the base of the synchronization transistor to the positive side of the DC power supply via a high resistance part, and connect it in parallel with the high resistance part. , a discharge lamp lighting device connected to a bypass circuit consisting of a series circuit of a low-resistance section and a switch that opens a predetermined section including at least the section from the zero point to a predetermined phase for each cycle of the pulsating output voltage of a DC power supply. Therefore, the oscillation part before the discharge lamp is re-ignited, which does not contribute to the light output of the load discharge lamp, can be stopped, and the smoothing capacitor can be charged before the inverter oscillation starts, making it a permanent source. It was possible to obtain a discharge lamp lighting device in which the resistance can be made high and the oscillation can be easily started while suppressing power loss.

For reference, FIG. 7 shows an example in which the present invention is applied to step dimming of a lighting device in which a DC power source with a pulsating output is completely smoothed.

That is, in the case shown in FIG. 7, a power supply smoothing capacitor C1 is connected to the DC output side of the rectifier circuit 1b via an inductor L1 for preventing rush current, and a synchronizing transistor 1 is connected to the DC output side of the rectifier circuit 1b.
The other end of the resistor 14a, one end of which is connected to the base side of 1,
To the positive end of the power supply smoothing capacitor C1 via the contact λ on the fully lit side of the switch S1.

They are each connected to the positive end of the rectifier circuit 1b via the contacts on the dimming lighting side.

In such a device, when all lights are on, the changeover switch SI is turned on to the contact λ side, and the bypass capacitor 16 is connected to the resistor 1.
However, as shown in FIG. 8(a), the terminal voltage Vc of the capacitor I6 is charged via the power supply smoothing capacitor C.
Since the terminal voltage Vc1 of I becomes the value divided by the resistors 14a, +46 and is always KVc1) Va, the synchronizing transistor 11fd always obtains a base current, and the oscillating transistor 6.7 performs on/off operation throughout the entire period. ,
When dimming, the selector switch S is turned on to the ti contact side,
As shown in FIG. 3B, oscillation is stopped only in a section 11 where the terminal voltage vO of the capacitor 16 is higher than the pulsating output voltage vl of the DC power source 1, and a dimming state is obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional example, FIG. 2 is a waveform diagram for explaining the same, FIG. 8 is a circuit diagram showing an embodiment of the present invention, and FIG.
The figure is a waveform diagram for explaining the same as above, FIG. 6 is a circuit diagram showing a specific circuit example of the present invention, FIG. 6 is a waveform diagram for explaining the same as above,
FIG. 7 is a specific circuit diagram showing an application example of the present invention. l... cσ current power supply, 2... inverter, 8... oscillation transformer, 4... discharge lamp, 6.7... oscillation transistor. 8...Drive winding, lO...Smoothing capacitor,
11... Switch for the same JUJ, 15... Bypass circuit, S... Switch. Patent Applicant Matsushita Electric Works Co., Ltd. Representative Patent Attorney Toshimaru Takemoto (and 2 others) Figure 1 Ss2 Figure 3 Figure 4 Procedures Amendment C Method) December 1982
Month Kutoto Date 1982 Patent Application No. 148287 2 Name of the invention Discharge lamp lighting device 3 Name of the person making the amendment Name (583) Matsushita Electric Works Co., Ltd. Address 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. Patent Division Name (6201) Patent Attorney Satoshi Takemoto
Circle 5, Date of amendment order: November 12, 1982 (shipped on November 30, 1987) 6. Subject of amendment: single +* "Brief explanation of drawings" column 7, Contents of amendment '917. ' Procedural amendment Showa Dan, 30th January, 1982, Patent Application No. 148287 2, Name of the invention: Discharge lamp lighting device 3, Name of the person making the amendment: (583) Matsushita Electric Works Co., Ltd. Representative: Iku Kobayashi 4; Agent's specification and drawing 7, content of amendment +11 Deletion of specification, page 1, line 9 to page 11, line 9. +21 Same as above, page 11, lines 18 to 19, “, 7th
The diagram is...a diagram. ” to be deleted. (8) Figures 7 and 8 of the drawings will be deleted.

Claims (1)

[Claims] (1) A DC power supply consisting of a rectifier 1- of an AC power supply, and an oscillation transistor for switching the DC power supply. An oscillation transformer that generates an AC output as the oscillation transistor switches, a discharge lamp connected to the output side of the oscillation transformer, a feedback winding provided in the oscillation transformer to control the oscillation transistor, and a feedback winding connected to the AC output. A drive winding that detects the corresponding output, a rectifier circuit connected to the output end of the drive winding, a smoothing capacitor connected to the DC side end of the rectifier circuit and supplying base current to the oscillation transistor, and a smoothing capacitor connected to the output end of the drive winding. A synchronous ITI in which the resistor is inserted between the capacitor and the base and emitter of the oscillation transistor and is connected to the positive side of the DC power supply via a high resistance part.
) A series circuit consisting of a transistor, a switch that opens a predetermined section including at least the section from the zero point of the voltage to a predetermined phase for each cycle of the pulsating output voltage of the DC power supply, and a low resistance section, and corrects the DC power supply. A discharge lamp lighting device comprising: a bypass circuit connected between the base end of the synchronizing transistor and the base end of the synchronizing transistor.